BWidget <<TreeSelect>> + keyboard navigation

I'm having problems with a BWidget Tree in one of my applications--it doesn't seem to fire the <<TreeSelect>> virtual event when the arrow key is pressed, either up or down. I'm binding a command to this event, so I have to get this working.

This is typical of what I've tried:

bind $Tree <KeyPress-Up> <<TreeSelect>>

Doesn't work.

Do I need to do something with [event generate] here? Has anyone found a way to implement this? I'm having some difficulty getting the syntax right.

Thanks for any pointers,
Kevin
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